Proceedings of the 49th Annual ASTRO Meeting S277

2136 Hyperfractionated Accelerated Radiotherapy for Rectal Cancer in Patients With Prior Pelvic Irradiation

P. Das, M. E. Delclos, J. M. Skibber, M. A. Rodriguez-Bigas, B. W. Feig, C. Eng, M. Bedi, S. Krishnan, N. A. Janjan, C. H. Crane

U.T. M.D. Anderson Cancer Center, Houston, TX

Purpose/Objective(s): To retrospectively determine rates of acute and late toxicity, pelvic control and survival in rectal cancerpatients treated with hyperfractionated accelerated re-irradiation.

Materials/Methods: Between February 2001 and February 2005, 50 patients with a prior history of pelvic radiotherapy weretreated with hyperfractionated accelerated radiotherapy for primary (N = 2) or recurrent (N = 48) rectal adenocarcinoma. The priorcourse of radiotherapy was given for rectal or rectosigmoid cancer in 43 (86%) and other malignancies in 7 (14%) patients. Themedian dose of the prior course of radiotherapy was 47 Gy (range 25–70 Gy), and the median interval between the two courses ofradiotherapy was 2.3 yrs (range 0.4–29.5 yrs). Reirradiation was administered to the recurrent tumor with a 2–3 cm margin. Patientswere treated with 150 cGy fractions twice daily, with an interval $6 hrs between fractions. Reirradiation was given with a total doseof 39 Gy (N = 47) if the retreatment interval was $1 yr, or with a total dose of 30 Gy (N = 3) if the retreatment interval was\1 year.Concurrent chemotherapy was administered to 48 (96%) patients. Eighteen patients (36%) underwent surgical resection followingradiotherapy, and 9 of these patients received intra-operative radiotherapy (IORT) with a dose of 10–15 Gy. The median follow-upwas 20 (range 0.3–67) months for all patients and 31 (range 6–67) months for surviving patients.

Results: The highest grade of acute toxicity during reirradiation was grade 0 in 9 (18%), grade 1 in 21 (42%), grade 2 in 18 (36%)and grade 3 in 2 (4%) patients. The grade 2 acute toxicities included diarrhea, nausea/vomiting, fatigue, anorexia, anemia, cystitisand skin toxicity. Nausea/vomiting was the only acute grade 3 toxicity. All patients completed reirradiation, and only two patientswere hospitalized for acute toxicity during chemoradiation. Eleven patients (22%) had grade 3–4 late toxicity, incuding smallbowel obstruction (N = 3), wound complication/infection (N = 2), pelvic abscess (N = 2), cystitis (N = 1), stricture (N = 1) andfistula (N = 1). The risk of grade 3–4 late toxicity was higher in patients with surgery (p = 0.004), IORT (p = 0.007), or cumulativeradiotherapy dose .90 Gy (p = 0.002). The median duration of pelvic control was 21 months, and the 3-yr pelvic control rate was36%. The 3-yr pelvic control rate was 47% in patients undergoing surgery, and 20% in those not undergoing surgery (p = 0.067).The median overall survival was 28 months, and the 3-yr overall survival rate was 48%. The 3-yr overall survival rate was 76% inpatients undergoing surgery, and 31% in those not undergoing surgery (p = 0.002). The 3-yr overall survival rate was 65% in pa-tients with retreatment interval .2 yr, and 29% in those with retreatment interval #2 yr (p = 0.001). On Cox multivariate analysis,surgery (p = 0.018) and retreatment interval .2 yr (p = 0.014) were independently associated with higher overall survival.

Conclusions: This regimen of hyperfractionated accelerated reirradiation was well tolerated with low rates of acute toxicity andmoderate rates of late toxicity. Reirradiation may help improve pelvic control in rectal cancer patients with a history of prior pelvicradiotherapy. Patients undergoing reirradiation and surgery can have high rates of overall survival.

Author Disclosure: P. Das, None; M.E. Delclos, None; J.M. Skibber, None; M.A. Rodriguez-Bigas, None; B.W. Feig, None;C. Eng, None; M. Bedi, None; S. Krishnan, None; N.A. Janjan, None; C.H. Crane, None.

2137 Adjuvant Chemoradiation Therapy After Pancreaticoduodenectomy in Elderly Patients With

Pancreatic Adenocarcinoma

D. P. Horowitz, C. C. Hsu, M. J. Swartz, M. A. Makary, J. M. Winter, R. Robinson, T. M. Pawlik, R. D. Schulick,J. L. Cameron, J. M. Herman

Johns Hopkins University School of Medicine, Baltimore, MD

Purpose/Objective(s): The United States elderly population will increase 50% within the next 15 years. Among elderly patientswith pancreatic adenocarcinoma, age has not been a contraindication to pancreaticoduodenectomy (PD) in terms of increased mor-bidity or mortality. To evaluate the utility of adjuvant postoperative chemoradiation therapy in this population, we evaluated acohort of patients aged 75+ who underwent PD with curative intent for pancreatic adenocarcinoma with and without adjuvant treat-ment.

Materials/Methods: All patients who underwent PD for pancreatic adenocarcinoma at the Johns Hopkins Hospital between 8/30/93 and 2/28/05 were reviewed. Perioperative/mortality within 60-days, patients who received vaccine, neoadjuvant therapy, andincomplete records were excluded. Survival was by review of follow-up information, cancer center abstracting services, and SocialSecurity Death Index. Demographic characteristics, past medical history, intraoperative data, histological diagnoses, pathologydata, and patient outcomes were compared by adjuvant treatment status and age. Cox proportional hazards analysis was used todetermine clinical predictors of mortality and morbidity among 734 PD patients, using STATA, version 8. Co-variates includedsex, race, co-morbid disease, tumor size, stage, node positivity, margin status, tumor differentiation, surgery type, and post-oper-ative complications.

Results: Of 734 patients who underwent PD with curative intent, 185 (25.2%) were $75 years of age and comprised our studypopulation. Of these patients, 56 (30.2%) received additional adjuvant chemoradiation therapy. The median survival for elderlyPD patients was 18.5 months vs. 14.0 for patients who did and did not receive adjuvant therapy, respectively (p = N.S.). Non-elderly patients had median survival with and without adjuvant treatment of 21.4 months vs. 13.9 months, respectively (p \0.001) Age 75 or greater slightly increased risk of mortality, but was not statistically significant (RR 1.18, p = 0.08). Amongthe subgroup of patients with treatment toxicity data available, unplanned treatment breaks were equal among the elderly andnon-elderly (26.9% and 23.0%, respectively, p = N.S.). Adjusting for major confounders, among the non-elderly adjuvant treat-ment was significantly associated with survival (RR 0.71, p = 0.002), whereas, among the elderly the protective effect of adjuvanttreatment was less evident (RR 0.84, p = N.S.).

Conclusions: Among the non-elderly, adjuvant therapy after PD is significantly associated with survival. However, among theelderly, the beneficial effect of adjuvant therapy on long-term survival may be diminished, warranting further improvements ofchemoradiation therapy in this vulnerable population.

Author Disclosure: D.P. Horowitz, None; C.C. Hsu, None; M.J. Swartz, None; M.A. Makary, None; J.M. Winter, None;R. Robinson, None; T.M. Pawlik, None; R.D. Schulick, None; J.L. Cameron, None; J.M. Herman, None.